Aftertreatment systems include various components that are positioned inside a housing. The housing of the aftertreatment system is mounted on a chassis or a frame of an apparatus (e.g., a vehicle or a generator set) via mounting members or fasteners. Temperature changes, for example due to hot exhaust gases passing through the housing, very high or low ambient temperature, etc. can cause the housing of aftertreatment systems to expand or contract. Aftertreatment systems are mounted to frames or chassis using fasteners. However, fasteners or mounting assemblies are not configured to accommodate thermal expansion or contraction of the housing of aftertreatment systems. This can cause stresses to develop at the mounting locations of the housing. Particularly large aftertreatment systems can experience significant expansion, for example in the order of a few centimeters. The mechanical stresses developing in the housing of such aftertreatment systems at the mounting locations due to thermal expansion/contraction can ultimately lead to cracks or otherwise damage to the housing of the aftertreatment system, the mounting hardware, frame or chassis.